Recovery boiler

摘要

A boiler recovers a soda component from pulp spent liquor and is able to prevent carry-over of unburnt char and deformation of a char bed configuration and to attain a stable combustion with low NOx generation. By regulating the combustion air supply, and feeding inert gas along a furnace side wall around the char bed, there are formed a combustion zone of reduction atmospheric field where air ratio in the surroundings of the char bed is 0.8 or less, a combustion zone of reduction atmospheric field where air ratio is 1.0 or less and unburnt components exist (including the case of a reduction atmospheric field where air ratio is 1.0 or less and unburnt components exist with the two combustion zones being combined together) and a combustion zone where combustion is completed.